18
HAMPTON ROADS BRIDGE TUNNEL
APPROACH TRESTLE REPAIRS
Andrew Zickler, PE
VDOT Structure and Bridge Division
Complex Structures and ABC Support Program Manager
CFRP Prestressed Beam Repairs
June 25, 2019
AASHTO Annual COBS Meeting
• Hampton Roads Bridge Tunnel (HRBT) carries I-64 across
Hampton Roads.
• All repair work was done to the two southern approach trestles
• HRBT trestles were opened 1957 (WB) and 1974 (EB).
Project Orientation
Virginia Department of Transportation
Project Location
Virginia Department of Transportation
Trestle
Virginia Department of Transportation
Approximately 9000LF of
trestle, each way
Clearance is near low tide
• The channel over the tunnel is major international cargo and
US Navy passage.
• Severe Deterioration was noted during routine inspections
• Additional issues were noted during patching operations;
• Line girder rating required posting.
• Grid analysis eliminated need for posting if deterioration stopped
• Several alternatives were evaluated for repairs.
• Due to lack of familiarity with
proposed repair approaches
and a wide range of loss of
section several approaches
were proposed
Critical Link with Critical Needs
Virginia Department of Transportation
Serious deterioration
Virginia Department of Transportation
Worst examples of strand loss
The solution at this level was
not a wrap. This was repaired
with external PT.
• External PT was eventually designed for the worst conditions
where additional capacity was required to meet service and
strength level conditions.
• Wrap was designed for beams which passed service level
requirements but required additional capacity for strength
Repair Selection
Virginia Department of Transportation
Beams in 1957 were similar to Type 3 with Gr 250 7/16” dia. SR
strands,. In 1974 similar to Type 4 with Gr 270 ½” dia SR strands
• Mock ups were proposed for PT using beams which had been
stored on site since construction.
• 2 1957 beams and 2 1974 beams were retrieve for PT markup
• Contractor asked to retrieve an extra beam for CFRP (making total of 5
beams. A formal mockup was added for CFRP wrap during
construction
• Beams were salvaged from a nearby bridge to increase the testing
sample.
Virginia Department of Transportation
Mock up beams
• Anchor at ends of CFRP repair was difficult to install due to the sharp inside corner at
the web to flange transition.
• Contractor asked to build up epoxy; that was rejected due to thermal incompatibility.
• VDOT proposed an alternative wrap layout to reduce pullout when wet, contractor
rejected
Virginia Department of Transportation
Lessons from CFRP Mockup
Contractor and VDOT agreed to single piece covering horsetail anchors
• VDOT has several additional structures with similar exposures
for which these repair types are being considered
• Getting information related to the efficacy for restoration of
load was considered important enough to warrant follow up
testing (testing coming August 2019)
Lab testing
Virginia Department of Transportation
• The patching was under a separate contract (using shotcrete)
• Drilled holes for the horsetail anchorages were made easier by use of pachometer to
determine rebar location
• Installation was fairly easy. It was complicated by an inside curve on both sides with
sharp corners
• A proposal was submitted for a build up to soften the radius with an epoxy build up. this was rejected
due to the change in the properties in thick epoxy layer. An alternative to lap multiple layers to avoid the
massive rework was approved.
CFRP Installation.
Virginia Department of Transportation
Shotcrete patching Surface prep for CFRP after patching
CFRP Installation
Virginia Department of Transportation
CFRP Installation
Virginia Department of Transportation
CFRP Installation
Virginia Department of Transportation
CFRP Installation
Virginia Department of Transportation
I was not able to get final step.
Last step is to seal beam and
CFRP wrap repair
Closing thoughts
Virginia Department of Transportation
VDOT is very satisfied at the conclusion of the construction
process
Installation went very quickly and smoothly with no significant
hiccups during the wrap installation
We are waiting for confirmation from the Lab.
We have other major structure where this is potentially a
solution to extend the life of the superstructure
The trestles will be removed from service by 2024
Questions?
Virginia Department of Transportation
Contact Information:
Andy Zickler
Program Manager, Complex Bridge and ABC Support Section
VDOT Structure and Bridge Division.
Fort Wool,
@ South Island:
National Historic Site
